1. Field of the Invention
The present invention relates to a very thin semiconductor package mounting a very thin semiconductor chip, multichip module (MCM) in which plural pieces of the very thin semiconductor packages are laminated, and manufacturing method for the same very thin semiconductor package and MCM.
2. Description of the Related Art
FIG. 1 is a cross sectional view of a conventional MCM in which the semiconductor packages are laminated. This MCM has a structure in which two semiconductor packages are laminated by tape carrier package (TCP) architecture in a space having a restricted height. In the lower TCP, Cu wiring layers 104a, 104j are disposed on a polyimide film 101, which is an insulating substrate. End portions of the Cu wiring layers 104a, 104j are connected to inner leads 203a, 203j. The inner leads 203a, 203j are connected to bonding pads of a silicon chip 94. Further, the silicon chip 104 is bonded to the insulating substrate 101 with insulating adhesive (not shown). A top portion of the silicon chip 94 and the inner leads 203a, 203j are sealed with sealing resin layer 95 made of epoxy or the like. Cu wiring layers 105a, 105j are disposed on a surface of the polyimide film 102 on the upper TCP. End portions of the Cu wiring layers 105a, 105j are connected to inner leads 204a, 204j, and the inner leads 204a, 204j are bonded to bonding pads disposed on the silicon chip 96. Further, the silicon chip 96 is attached to the insulating substrate 102 with insulating adhesive (not shown). A top portion of the silicon chip 96 and the inner leads 204a, 204j are sealed by sealing resin layer 97. In such a conventional semiconductor package having upper/lower levels structure, the thickness of the silicon chips 94, 96 is about 200 xcexcm. Thus, the thickness of each package is 350 xcexcm to 500 xcexcm. Therefore, the bending strength of the package is relatively high so that there is little possibility that the package may crack when bent.
There are increasing demands recently for reductions in thickness, geometrical size, weight and the like in the field of IC cards, portable information instruments or mobile multimedia applications and the like. However, because the height of the package from its mounting face of the MCM substrate is quite high, the MCM shown in FIG. 1 is not capable of satisfying the recent demands such as the reduction in thickness.
Accordingly, the present invention has been conceived to solve the above described problems and, therefore, it is an object of the invention is to provide a very thin semiconductor package suitable for a stacked structure, and strong against stress in a bending direction.
Another object of the invention is to provide an MCM, which is very thin in total thickness, and has a high breaking strength when the semiconductor packages are laminated.
More specifically, it is still another object to provide a very thin MCM in which an occurrence of crack in the package due to stress in the bending direction is prevented effectively.
A still another object of the present invention is to provide a manufacturing method for a very thin MCM, having a high breaking strength.
To achieve the above object, a first feature of the present invention inheres in a semiconductor package having: insulating substrates; wiring layers disposed on the surface of the insulating substrate; a semiconductor chip disposed in a device hole provided in the insulating substrate; inner-joint-conductors for connecting at least part of the bonding pads on the surface of the semiconductor chip to the corresponding wiring layers; and connection lands connected to the wiring layers. The device hole is provided so as to penetrate the central portion of the insulating substrate. The thickness of the semiconductor chip is smaller than that of the insulating substrate. Then, the semiconductor chip is disposed in the device hole such that a bottom thereof is flush with a bottom plane of the insulating substrate.
According to the first feature of the present invention, the thickness of the semiconductor chip is reduced smaller than the normally used thickness. As the semiconductor chip, an element semiconductor such as silicon (Si), germanium (Ge), etc. or a compound semiconductor chip such as gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), silicon carbide (SiC), etc. may be employed. And according to the semiconductor package of the first feature, a very thin semiconductor package is achieved.
A second feature of the present invention lies in laminated structure assembled by plural pieces of the semiconductor packages, each of the semiconductor packages is already stated in the first feature of the present invention. That is, according to the second feature of the present invention, first and second semiconductor packages, each having the above-described first feature of the present invention, are laminated, for example. The first semiconductor package has: a first insulating substrate; first wiring layers disposed on the first insulating substrate; a first semiconductor chip disposed in a first device hole of the first insulating substrate; first inner-joint-conductors for connecting the first bonding pads to the first internal wiring layers; first connection lands connected to the first wiring layers. On the other hand, the second semiconductor package has a second insulating substrate disposed above the first insulating substrate; second wiring layers disposed on the second insulating substrate; a second semiconductor chip disposed in the second device hole of the second insulating substrate; second inner-joint-conductors for connecting the second semiconductor chip to the second wiring layers; and second connection lands electrically connected to the first connection lands.
Here, the first device hole is formed so as to penetrate the central portion of the first insulating substrate. Likewise, the second device hole is formed so as to penetrate the central portion of the second insulating substrate. The thickness of the first and second semiconductor chip is smaller than that of the first and second insulating substrates. The first semiconductor chip is disposed in the first device hole such that a bottom thereof is flush with a bottom plane of the first insulating substrate. The second semiconductor chip is disposed in the second device hole such that a bottom thereof is flush with a bottom plane of the second insulating substrate. The first inner-joint-conductors connect at least part of the first bonding pads on the first semiconductor chip to the corresponding first wiring layers. The second inner-joint-conductors connect at least part of the second bonding pads on the second semiconductor chip to the corresponding first wiring layers.
According to the MCM of the second feature of the invention, plural pieces of the thin semiconductor packages are laminated on the MCM substrate. And the upper and lower semiconductor packages in a vertical direction are connected through their predetermined connection lands. Therefore, the thin semiconductor packages can be stacked in multi-levels in a preferable fashion, thereby the stacked performance being remarkably improved. If the present invention is applied to, for example, a media card of a digital camera, the media card having a large memory capacity despite a small size can be achieved. Further, because the semiconductor packages are laminated with the top and bottom surfaces of the thin silicon chips inverted and the predetermined connection lands are electrically connected, they can be stacked such that weak portions of the thin semiconductor packages are not aligned on the same projection plane. As a result, the breaking strength of the MCM when the semiconductor packages are laminated is increased and the portion of the package weak to stress in the bending direction can be reinforced, so that an occurrence of crack in the package can be prevented.
Further, because the wiring layer corresponding to an electrode designed not to be electrically connected may be cut off in the package level, just before a lamination process, it is possible to assign each of chips in stacked semiconductor packages with a specific address and determine wiring layout for selection of the specific address. As a result, the respective stacked thin silicon chips can be operated independently of each other.
According to a third feature of the present invention, the first and second semiconductor packages are laminated like the MCM of the second feature. Here, the first semiconductor package has: a first insulating substrate; first wiring layers disposed on the first insulating substrate; a first semiconductor chip disposed above a main surface of the first insulating substrate; first inner-joint-conductors for electrically connecting at least part of the first bonding pads to the corresponding first wiring layers; and a first sealing member filled between the first insulating substrate and the first semiconductor chip. On the other hand, the second semiconductor package has a second insulating substrate shifted by a predetermined distance along a plane parallel to the first insulating substrate relative thereto, having second wiring layers electrically connected to the first wiring layers; a second semiconductor chip disposed above the main surface of the second insulating substrate; second inner-joint-conductors for electrically connecting at least part of the second bonding pads to corresponding one of the second wiring layers; and a second sealing member filled between the second insulating substrate and the second semiconductor chip.
According to the MCM of the third feature of the present invention, plural pieces of the thin semiconductor packages are laminated on the MCM substrate, and conductors connect the upper and lower semiconductor packages through their predetermined electrodes. Therefore, the thin semiconductor packages can be stacked in multi-levels in a preferable fashion, thereby the stacked performance being remarkably improved. Further, because the respective semiconductor packages are placed so that they move horizontally with respect to the plane of a lower semiconductor package and the predetermined electrodes are electrically connected, the mechanical strength is made uniform so that an occurrence of crack in the package becomes hard to occur. Further, it is not necessary to prepare two kinds of the mirror symmetrical packages, and therefore the number of the kinds of necessary packages can be reduced.
A fourth feature of the present invention lies in a method for manufacturing a multi-chip module having the steps of: (a) thinning a first semiconductor chip having first bonding pads and a second semiconductor chip having second bonding pads to 10 xcexcm-150 xcexcm in thickness, respectively; (b) delineating package wirings on a main surface of a MCM substrate; (c) preparing a first insulating substrate having a first device hole and a second insulating substrate having a second device hole; (d) delineating first wiring layers and first connection lands connected to the first wiring layers on the first insulating substrate; (e) delineating second wiring layers and second connection lands connected to the second wiring layers on the second insulating substrate; (f) placing the first and second insulating substrates on a table so as to mount the first and second semiconductor chips in the first and second device holes; (g) connecting the first bonding pads to the corresponding first wiring layers through first inner-joint-conductors; (h) connecting the second bonding pads to the corresponding second wiring layers through second inner-joint-conductors; (i) sealing the first semiconductor chip and the first inner-joint-conductor with resin and sealing the second semiconductor chip and the second inner-joint-conductor with resin; j) mounting the first insulating substrate on the MCM substrate so as to electrically connect the package wirings to the first connection lands; and (k) mounting the second insulating substrate on the first insulating substrate so as to electrically connect the first connection lands to the second connection lands.
A fifth feature of the present invention lies in a method for manufacturing a multi-chip module having the steps of: (a) thinning a first semiconductor chip having first bonding pads and a second semiconductor chip having second bonding pads to 10 xcexcm-150 xcexcm in thickness, respectively; (b) delineating package wirings on a main surface of a MCM substrate; (c) preparing a first insulating substrate and a second insulating substrate; (d) delineating first wiring layers on the first insulating substrate; (e) delineating second wiring layers on the second insulating; (f) depositing selectively a sealing member in a first chip mount region on a main surface of the first insulating substrate, mounting the first semiconductor chip at the position of the sealing member and connecting the first bonding pads to the corresponding first wiring layers through first inner-joint-conductors; (g) depositing selectively a sealing member in a second chip mount region on a main surface of the second insulating substrate, mounting the second semiconductor chip at the position of the sealing member and connecting the second bonding pads to the corresponding second wiring layers through second inner-joint-conductors; (h) mounting the first insulating substrate on the MCM substrate and connecting electrically the package wirings to the first wiring layers; and (i) mounting the second insulating substrate on the first insulating substrate by shifting it by a predetermined distance along a plane parallel to the first insulating substrate relative thereto and connecting electrically the first wiring layers to the second wiring layers.
Other and further objects and features of the present invention will become obvious upon an understanding of the illustrative embodiments about to be described in connection with the accompanying drawings or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employing of the invention in practice.